A saw a lot of doujinshi about this series and this is different from the others.
Maybe it seems strange becouse understand the plot is difficault, unless you could read japanese. Moreover, the style of the draws is strange too, but not bad.
I think if you have a collection of doujinshi about keroro (sgt frog) you should have also this, however if you don't like this anime series then you probably don't enjoy this doujinshi.